This invention relates to surface-treatment barrier coating to provide protection against fire, and where appropriate against flammable fuel leakage, in relation to various fire-vulnerable structures, such as (a) structural steel columns, (b) structural steel beams, (c) wooden (or other) building-structure framing, (d) petroleum-based fuel containers (fuel tankers, pipelines, fuel storage tanks, etc.), (e) composite structures, such as composite armor structures, and (f) other like structures.
There are various fire-risk settings where crucial structures, including petroleum based fuel containers, such as those just generally mentioned above, can be threatened with destruction as a consequence of uncontrollable combustion. Good illustrations include (a) what took place in New York City on Sep. 11, 2001 where surface heating of structural columns led to column failure and devastating collapse of the World Trade Center Towers, and (b) the results of a recurrent tactic which has been employed widely in a current Middle East combat theater involving puncturing of the walls in petroleum-based fuel containers to create fuel leaks which then are intentionally ignited to create catastrophic and life-threatening fires. There are, of course, many other good illustrations of settings wherein the present invention can offer special utility.
The present invention takes aim at thwarting these kinds of events. It does so by proposing the creation of a sprayed-on, high-elastomeric-material coating which, in addition to containing an appropriate, tenacious, high-elastomeric material which offers special functionality as will be explained herein shortly, also at least includes, in an outer portion of such a coating, a distributed population of intumescence elements, such as sodium silicate crystals.
In an embodiment of the invention including simply the mentioned high-elastomeric material, and an appropriate distribution of intumescence elements, when this coating becomes exposed to high heat, such as a nearby fire, the intumescence elements rapidly react to such heat by expanding in an explosive, pop-corn like manner, thus to swell the thickness of the coating quickly in order to grow a significantly thickening heat-insulative barrier on a coated surface. With the mentioned high-elastomeric material effectively employed as an embedding material relative to the intumescence elements, this material enhances the resulting thickness “growth” behavior of the overall protective coating by holding together the expanded crystals as a promotion to coating thickening. Such an elastomeric material especially adds to the protective nature of this invention by enabling the progressive “growing” of coating thickness as outside fire heat continues progressively to raise, to intumescence “popping” temperature, sodium silicate crystals initially “un-triggered” because of their being deeply embedded in the embedding high-elastomeric material.
With such an embodiment of the invention, the first crystals to “pop”, and thus to begin effective coating-layer thickness growth, are those disposed near the outside of the coating relative to the structure on which the coating has been applied. As the coating thickness increases, and as “deeper” crystals eventually “rise” to popping temperature, there occurs, as one can appreciate, a significant, progressive enlargement of the depth (i.e., thickness) of the coating, which thus responds dynamically to inhibit protected-surface combustion by “driving” the heat of fire more distantly away from this surface.
Another fire-protective mechanism which is employed by the coating proposed by the present invention relates to an outer surface heat reaction which takes place whereby, shortly after the intense heat of a fire has been applied to the outside of the coating, and the coating has begun to respond with swelling intumescence behavior, there develops a heavy flow, somewhat like a blanket, of soot-infused smoke which, only for a relatively short period of time, is accompanied by the usual and expected powerful smell of “burning activity”. In other words, an emission of a blanket of such smoke has been observed to come from initial burning of the high-elastomeric material employed in the coating of the invention in a manner which, apparently, quickly creates a burned condition that thereafter “refuses” to furnish additional elastomeric material “fuel” for burning. In other words, coating elastomeric material burning appears to stop, per se, quite rapidly. An important consequence is that the body of elastomeric material stays together sufficiently to support the ever-thickening, protective growth of the coating.
Yet another important protective mechanism, dual-featured in nature, which is provided by the coating of this invention relates to the fact that the high-elastomeric material chosen for the coating is (a) a liquid-imbibing material which (b) also reacts chemically with petroleum-based fuel in what has been found to be a very useful coalescence way. This dual-feature mechanism is observed under circumstances where the coating has been applied to the outside surface of a wall-punctured, flammable petroleum-based fuel container, such as a transportable fuel tanker, or a fuel pipeline, as illustrations. If some aggressive activity causes a penetration, as by a bullet wound, through the coating of this invention, and also through a coating-protected fuel-container wall, resulting leaking petroleum-based fuel causes an imbibing and swelling reaction to take place with regard to the exposed and fuel-contacted elastomeric material, with a resulting congealing action occurring to create a sticky and tacky continuous mass which tends very quickly to close such a wound against further leakage. The elastomeric nature of the elastomeric material employed in the coating of this invention cooperates with this imbibing, chemically-reactive and congealing action to apply mechanical sealing pressure also to a puncture wound in the region around the congealing mass of reacted-with material.
Still a further protective approach proposed by the present invention includes creating a coating of the type generally mentioned above which additionally includes a layer region containing elastomeric-material-embedded, fuel-reactive, liquid-imbiber beads which function especially well at imbibing leakage petroleum-based fuel, and swelling greatly in size to furnish yet another puncture-wound sealing mechanism. These included imbiber beads also exhibit the kind of reactive congealing just mentioned above herein with respect to the embedding high-elastomeric material.
These and other various advantages and protection opportunities which are afforded by the present invention will become more fully apparent as the detailed description of the invention which now follows is read in conjunction with the accompanying drawings.
Structures presented in the several above-identified drawing figures are not necessarily drawn to scale.